Expired e-mail certificate and sent messages

A year ago I installed a free e-mail certificate that has expired. What I didn’t realize then - it’s only valid for a year. So if someone I sent e-mail over the past year opens one of those e-mails, he or she is presented a message there’s a problem with the signature. The problem being an expired certificate. So instead of introducing more secure e-mail by using a certificate, I created e-mails that look suspicious when that certificate expires. Not exactly what I had in mind. E-mail certificates sold by Comodo are only valid at best 3 years. So that’s no solution and I have to think of another way to sign e-mails.

But for those e-mails sent - I guess there’s no way for me to present them to the receiver as valid indefinitely?


I may be seeing it wrong, but can’t you renew the free certificate? If so, once you do that, you should be fine, right?

Also, the certificates that are valid for 3 years are able to be renewed, so after that, you’ll be back on your feet again I guess.